Political conflict over the respective roles of the state and the market in health care has a long history. Current interest in market approaches represents the resurgence of ideas and arguments that have been promoted with varying intensity throughout this century. (In practice, advocates have never wanted a truly competitive market, but rather one managed by and for particular private interests). Yet international experience over the last forty years has demonstrated that greater reliance on the market is associated with inferior system performance--inequity, inefficiency, high cost, and public dissatisfaction. The United States is the leading example. So why is this issue back again? Because market mechanisms yield distributional advantages for particular influential groups. (1) A more costly health care system yields higher prices and incomes for suppliers--physicians, drug companies, and private insurers. (2) Private payment distributes overall system costs according to use (or expected use) of services, costing wealthier and healthier people less than finance from (income-related) taxation. (3) Wealthy and unhealthy people can purchase (real or perceived) better access or quality for themselves, without having to support a similar standard for others. Thus there is, and always has been, a natural alliance of economic interest between service providers and upper-income citizens to support shifting health financing from public to private sources. Analytic arguments for the potential superiority of hypothetical competitive markets are simply one of the rhetorical forms through which this permanent conflict of economic interest is expressed in political debate.